Twin Screw Rotary Head Extruder, Method of Extrusion and Random Extruded Products

ABSTRACT

An improved rotary head extruder incorporates a twin auger system, in lieu of the typically used single auger, to create random extruded products having a density within the range of about 3.0 to about 6.0 lbs/cu ft. Extrusion using the rotary die system of a rotary head extruder together with the twin auger system allows for a wide variety of fine materials to be successfully introduced into and conveyed within a rotary head extruder to the die assembly, where the materials are cooked to form random extruded products. A transition piece at the downstream end of the augers allows for continuous, uniform flow to the die assembly, where cooking takes place. The random extruded products incorporate formulations with various ingredients aside from the typically used corn meal formulations, having different tastes and nutritional benefits while maintaining the desired bulk density, texture, and crunch of random extruded products.

BACKGROUND

1. Technical Field

The present invention generally relates to an improved rotary headextruder for the incorporation of ingredients that are otherwisedifficult to include within random extruded collets.

2. Description of Related Art

In the formation of random collet products, inclusion of componentsother than substantially uniform corn meal (i.e., of similar particlesize) or refined meals has proven difficult because of the limitationsof the rotary head extruder. FIG. 1 depicts the well-liked variety ofcorn collets known as random corn collets 2, which are produced by arotary head extruder. Random corn collets 2 comprise unique, twisted(“random”) shapes and protrusions and a highly desirable crunchy texturethat can only be produced with a rotary head extruder. It is a generallyaccepted fact in the industry that these kinds of extruders cannothandle flour-like or non-refined granular materials. As such, extruderformulations for random collets comprise only corn grits or corn meal,and water, to create the collets 2 of FIG. 1. While it may be possibleto incorporate some amounts of other ingredients to slightly modify thedirect expanded products, to date, these amounts are not large enough tosignificantly vary the varieties or tastes of random collet products.Moreover, introduction of small granular materials such as flour orpowder into a continuous random extrusion line typically causes blockageand halts production. Thus, there is a need for a rotary head extrudercapable of handling additional formulations on a continuous basis formass production. In particular, the introduction of ingredients otherthan corn into a rotary head extruder while mimicking the appealingcharacteristics of the random corn collet 2 is highly desirable; namely,taste, appearance, density, and mouthfeel (or texture). Such non-cornrandom collet products should emulate the organoleptic properties,including taste and texture, of a conventionally produced shelf stable(i.e., corn-based) and ready to eat random collet.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well asa mode of use, further objectives and advantages thereof, will be bestunderstood by reference to the following detailed description ofillustrative embodiments when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 depicts typical random corn collets as known in the industry.

FIG. 2 depicts a perspective view of a prior art rotary head extruderused in manufacturing collets.

FIG. 3A depicts a close-up view of the main working components of therotary head extruder depicted in FIG. 2.

FIG. 3B depicts a detailed cross-sectional view of the main workingcomponents of the extruder depicted in FIG. 2.

FIG. 4 depicts an exploded view of one embodiment of an improved rotaryhead extruder.

FIG. 5A depicts a top view of one embodiment of an assembled improvedextruder.

FIG. 5B depicts a cross-sectional side view of the twin auger systemwithin an improved rotary head extruder.

FIG. 6 depicts a forward view of the twin augers in one embodiment of animproved extruder described herein.

FIG. 7 depicts a random extrusion line process incorporating theextruder described herein.

SUMMARY

An improved rotary head extruder successfully replaces the typicallyused single auger within the extruder with a twin-screw system forcontinued production and high throughput rates of random extrudedproducts having a density within the range of 3.75-5.5 lbs/cu ft. Twoscrews (also referred to here as augers) are encased within a singlebarrel. A transition piece ensures delivery to a stator is continuousand uniform, ensuring proper flow of materials introduced into thebarrel of the extruder for extrusion. The stator is a stationary platesurrounding an output end of an interior conical portion downstream fromthe single barrel. A rotor, or rotatable plate, is downstream from thestator. The rotatable plate comprises a plurality of fingers surroundinga protruding nose cone located within a die gap, which is between thestator and the rotor.

Extrusion using the rotary die system of a rotary head extruder togetherwith the twin auger system described herein allows for a variety of fineparticle sizes, a wide particle size distribution, and raw materialcompositions to be successfully introduced into and conveyed within arotary head extruder to the die assembly, where the materials are cookedto form a wider array of random extruded products.

The random extruded products incorporate formulations with variousingredients aside from the typically used corn meal formulations, whilemaintaining the desired bulk density, texture, and crunch of randomextruded collet products. Other benefits and advantages of the presentinvention will become apparent to one skilled in the art.

DETAILED DESCRIPTION

To better understand the limitations of a rotary head extruder in termsof its typically used corn formulations, and the benefits of theimproved extruder and method described herein, a discussion of theconventional rotary head extruder is helpful.

Rotary head extruders use two round plates to cook and gelatinize cornmeal. One plate is rotating and the other is stationary, producingfriction necessary to produce random collets. These extruders arehigh-shear, high-pressure machines, which generate heat in the form offriction in a relatively short length of time. No barrel heating isapplied in rotary head extruders, as the energy used to cook theextrudate is generated from viscous dissipation of mechanical energy.There is no added water, heating element or cooling element used withina rotary head extruder to control temperatures. Instead, rotary headextruders use friction generated within the round plates (and not in theauger or screw zone) to cook the extrudate. There is no mixing and onlya very limited compression at the auger of a rotary head extruder;specifically, only enough to convey the material in the gap areas withinthe barrel. The shear is instead at the fingers 26 (best shown in FIG.3A), described below. While the auger zone helps transport materials tothe die assembly 10, it cannot mix materials and is a poor conveyer ofmixed materials and of certain ingredients, including very smallingredients such as powders or flours. Instead, the rotary head extruderis limited to refined cereal meal formulations within a narrow range ofparticle size. Anything else often results in flow irregularities alongthe single auger, which turns into blockages in the extruder flow,leading to failure and stoppages of the extruder. In addition, themaximum in-feed throughput capacity is limited to between about 400 toabout 450 lb/hr.

FIG. 2 illustrates a perspective view of a typical rotary head extruderused for production of the random corn collets 2 depicted in FIG. 1.Pre-moistened cornmeal is gravity-fed through a hopper 4 and into theextruder 6. The rotary head extruder 6 is comprised of two main workingcomponents that give the collets their twisted (“random”) shapes: asingle screw or auger 8 and a rotary die assembly 10. FIGS. 3A and 3Billustrate a close up and detailed side view image of the two mainworking components 12 of the extruder 6. The auger 8 is housed in acylindrical casing, or barrel 14, and comprises an open feed section 16through which the cornmeal passes, shown in FIG. 3. It should be notedthat the open feed section 16 is slightly turned in FIG. 3 to betterdepict the auger 8. In practice, the hopper feeds into the open feedsection 16 from above. While the barrel 14 is shown to be quite short inthe figures for clarity purposes, it should be noted that its portrayalis merely for purposes of depiction and the barrel length is not drawnto scale. The auger 8 transports and compresses the cornmeal, feeding itto the rotary die assembly 10, where it is plasticized to a fluidizedstate in a glass transition process further described below.

The die assembly 10 contains two brass alloy round plates: a stator 18(with the stationary plate) and a rotor 20 (the rotating plate).Gelatinization of moisturized starchy ingredients takes place inside theconcentric cavity between these two brass plates 18, 20. The stator 18is an assembly comprising a stator head section 22 and a roundstationary brass plate 24 that acts as a die through which thegelatinized melt flows. The stationary plate 24 has grooves 48 that aidin the compression of cornmeal as the stator 18 works together with therotor 20. The rotor 20 is a rotating plate comprising fingers 26 and anose cone 28. The nose cone 28 channels the cornmeal towards the fingers26 and helps discharge the gelatinized cornmeal through the small gapbetween the rotor 18 and stator 20. The action of the fingers 26 createsthe necessary condition of pressure and heat to achieve plasticizationof the raw materials at approximately 260° F. to 320° F. (127° C.-160°C.). Specifically, the fingers 26 force cornmeal back into the groovesof the stator head 24, causing friction and compression of the cornmealin the gap between the stator 18 and the rotor 20. The brass facing 32on the rotor 20 also helps to create heat and compression. Randomextrusion may thus be characterized by a thermo mechanicaltransformation of the raw materials brought about by the metal-to-metalinteractions of the die assembly 10.

Several things happen within the die assembly 10 during the randomextrusion process. First, the corn meal is subjected to high shear ratesand pressure that generate most of the heat to cook the corn. Thus,unlike other extruders, most of the cooking takes place in the rotarydie assembly 10 of the rotary head extruder. As stated above, there isno added water or external heat used to control the temperatures withinthis extruder. Second, a rapid pressure loss causes the superheatedwater in the corn mass to turn to steam, puffing the cooked corn as itexits the die assembly. Third, the flow of corn between one rotatingplate 20 and one stationary plate 18 twists the expanding corn leavingit twisted and collapsed in places, resulting in the productcharacteristic shape shown in FIG. 1. The random collets exit the rotaryhead extruder circumferentially outward from the gap between the statorand rotor in a radial path from the center of the fingers in the generaldirection of the straight arrows depicted in FIG. 3A. Cutter bladeswithin a cutter assembly then cut off the collets 2 that result from theexpansion process of the stator-rotor interactions. The process isentirely unique, providing unsystematic, irregularly shaped collets anda texture distinct in its crunchiness, giving somewhat of a homemadeeffect. Typical prior art corn meal specifications for rotary headextruders, for example, include a particle size distribution where nomore than 2.5% of the particles can be smaller than 300 microns. Theextruder described herein, on the other hand, can successfully processcornmeal with more than about 5%-10% of the particles smaller than 300microns. While other extruders may provide more flexibility in terms ofthe components introduced therein, only rotary head extruders canperform random extrusion and create the random collet 2, which upon exitfrom the extruder, comprises a unique shape and a bulk density rangingfrom between about 3.0 to about 6.0 lbs/cu ft. or more preferablybetween about 4.0 to about 5.25 lbs./cu ft.

FIG. 4 illustrates an exploded view of the components of an improvedrotary head extruder according to one aspect of the present disclosure.The rotary head extruder comprises a hopper 16, much like that of theabove described rotary head extruder of FIG. 3, through which rawmaterial is passed into a barrel 14. Materials may be introduced, forexample, through a hopper or other funnel device. Within the barrel 14is a twin screw system comprising two augers 42 a,b, also depicted inFIGS. 5A and 5B. A transition piece 40 surrounds an end portion of theaugers 42 a, b as best shown in FIGS. 5A and 5B. In one embodiment, thedistance between the external surfaces of the augers to the inner wallof the barrel 14 may range from between about 0.1 mm to about 0.150 mm.Flight elevates from the base of the auger will stop about 0.1 mm shortof the wall in one embodiment. The transition piece 40 fits snuglywithin the stator head section 22. The internal shape of the transitionpiece 40 presents a conical shape of flow path 44, best shown in FIG. 6.A figure eight shape is shown on the upstream end of the interiorconical flow path 44. The interior conical flow path 44 surrounds an endof each of the auger 42 a, b, the conical interior shape comprising afigure-eight shape at its base or upstream end, which diverges to a widecircular downstream end.

Referring to FIG. 5A, in one embodiment, the improved rotary headextruder comprises a twin auger system comprising or consisting of tworotatable augers 42 a, 42 b within a single barrel 14; a transitionpiece 40 at a downstream end of the rotatable augers 42 a, 42 b, thetransition piece having a figure eight opening comprising a funnelshape; and a die assembly 10 comprising or consisting of a stator 18 anda rotor 20 with a die gap there between, wherein the stator comprises astationary plate 24 surrounding an output end of the transition pieceand the rotor 20 is a rotatable plate downstream from the stator, therotatable plate comprising a plurality of fingers 26 surrounding aprotruding nose cone 28 of the rotatable plate located within the diegap. The single barrel 14 is positioned at the end of a shaft controlledby a gear box (not shown) and moveably positioned such that the fingers26 surround downstream ends of the two augers 42 a, b when the extruderis operated to undergo random extrusion of food materials. It should benoted that one of the fingers 26 in FIG. 5A is shown only in part so asto better depict the nose cone 28. In practice, each of the fingers 26comprise the approximate same length and circumferentially surround thenose cone as well as at least a portion of the downstream ends of thetwo augers 42 a, b. Each of the two augers is located equidistant to andon opposing sides of the nose cone in one embodiment. FIGS. 5A and 5Bdepict the stator 18 and rotor 20 with the small die gap there between,which is present during operation of the rotary head extruder. In oneembodiment, the die gap is between about 1.25 mm and about 2.54 mm. Asdescribed above with the prior art rotary head extruder, cooked andexpanded or puffed product will exit the extruder circumferentiallyoutwards from the die gap.

FIG. 6 depicts an interior conical flow path 44 between the externalsurfaces of the augers 42 a, 42 b and the walls of the barrel 14. Theinterior conical flow path 44 encloses an end of the two augers 42 a, 42b tightly, forming a figure eight opening at the most upstream end ofthe transition piece 40 towards the barrel 14. The opening remainsconstant for a length along a downstream end of the augers and thenfunnels out, widening at the exit end of the material to be plasticizedin the two bronze plates. The single barrel 14 houses the two augers 42a,b and extends horizontally along at least half their connecting withthe transition piece 40 and into the FIG. 8-shape of the conical flowpath 44. While depicted as a separate piece in the figures, thetransition piece 40 may also be an integral part of the stator headsection 22 adjacent to the downstream end of the augers.

Returning to FIGS. 5A and 5B, the stator 18 comprises a stator headsection 22 with interior grooves 46 at its outlet end. The interiorgrooves are preferentially horizontal and circumferentially spacedaround the circular opening. In addition, the interior grooves 46 shouldsubstantially align at their downstream ends with the grooves 48 of thestationary plate 24, which surrounds the outlet end of the stator head22. In one embodiment, the stationary plate 24 is comprised or consistsof bronze. Other metals may also be possible so long as friction remainsgenerated in operation. On the upstream end, the interior grooves 46meet with the downstream end of the transition 40 and interior conicalflow path 44, the conical shape having a slope extending outwards tomeet with the interior grooves 46. Thus, the interior conical flow path44 comprises a funnel-like shape with its wide end facing the grooves 46of the stator 18. In one embodiment, the slope of the interior conicalportion of the transition piece 40 begins at a location behind the twoaugers, or at their downstream tip ends, to meet the interior grooves 46of the stator head section 22. In one embodiment, the slope is less thanabout 75 degrees. In one embodiment, the slope is less than about 65degrees. In one embodiment, the slope is less than about 60 degrees. Theslope should generally allow for a smooth transition and continuous flowof extrudate to the die assembly. In one embodiment, the stator headsection 22 surrounds the interior conical portion 44, which provides fora quick transition or short slope end portion between the two auger endsand the stator 18. As perhaps best shown in FIG. 5B, the transitionpiece 40 comprises an upstream portion having a substantially constantor equal thickness along its length. This equivalent upstream stemportion spans at least half the length of the transition piece 40. Thedownstream end of the transition piece 40 comprises a funnel like shape,which slopes out to a conical mouth with a wider opening at its mostdownstream end. The interior conical portion provides for smooth flow ofmaterials to the die assembly 10, where they will ultimately be cookedand puffed. The rotor 20 has its own motor drive (not depicted) tocontrol the speed and rotation of the rotor during extrusion.

By successfully incorporating a twin-screw system into an extruder thatis still capable of producing random extrusion processes, the transferof granular materials inside the extruder to the rotary die is improved.The twin screw rotary head extruder described herein improves thestability of the overall process and creates a robust random extrusionsystem capable of accepting a wide variety of raw materials forproduction of diverse random collets. During random extrusion, the twoaugers 42 a, b may rotate independently (actuated by separate powersources or a transmission gear) but in the same direction to provide forintermeshing effects to convey materials between the walls of the singlebarrel and the augers. In one embodiment, the two augers are connectedvia a gearbox. As depicted in FIGS. 5A and 5B, in one embodiment, theaugers are positioned horizontally within the single barrel adjacent toone another. However, in one embodiment, the augers 42 a,b may also beposition vertically, or one on top of the other. In one embodiment, thetwo augers will rotate at speeds of between about 150 to about 500 rpm.In another embodiment, the two augers will rotate at speeds of betweenabout 200 to about 350 rpm. In another one embodiment, the two augerswill rotate at speeds of between about 300 to about 320 rpm.

The twin-auger system is self-wiping and closely intermeshing,transferring materials by a positive displacement action by itsco-rotating mechanism, which makes the process more independent of thenature and composition of the raw material. Transfer limitations due toconstituents of the raw material difficult to convey such as fiber, oilyparticles, small particulates, or other lubricant-acting components areovercome and conveyance is improved. There remains no added water,heating element or cooling element used within the rotary head extruderdescribed herein. The energy used to cook the extrudate is generatedfrom the friction of the die assembly. There are no holes or openings ineither the stator or rotor, and the random collets exit the rotary headextruder circumferentially outward from the gap between the stator androtor.

The twin screw rotary head extruder described herein can successfullyhandle continuous random extrusion of varied materials as well asmaterials of variable sizes. For example, corn meal having a wide rangeof particle sizes has been successfully tested, including those thathave previously imparted challenges due to the very different particlessizes of the corn meal. In one embodiment, a particle size distributionof between 200 and 900 micrometers can be fed into the rotary headextruder of the present disclosure and successfully random extruded. Inthis embodiment, up to or about 80% by weight of the particle sizedistribution may comprise fine particle size of about 400 micrometers.In other embodiments, the particles may range from about 200 to about1200 micrometers, with optionally about 50% of the particle sizedistribution reaching up to or about 400 micrometers. Additionalembodiments and examples are provided below.

In accordance with another aspect of the present disclosure is a methodof random extrusion comprising the steps of feeding raw materials into asingle barrel comprising or consisting of two augers positioned within atightly fitting encasing within the single barrel; and conveying the rawmaterials towards a die assembly through an intermeshing mechanism ofthe augers, said die assembly comprising a stator and a rotor with a diegap there between, wherein the stator is a stationary plate surroundingan output end of the single barrel and the rotor is a rotatable platedownstream from the stator, the rotatable plate comprising a pluralityof fingers surrounding a protruding nose cone of the rotor locatedwithin the die gap. In one embodiment, the raw materials pass through aninterior conical portion prior to reach the rotary die assembly.

As depicted in FIGS. 5A and 5B, the nose cone of the rotor protrudesinwardly with its tip facing the stator such that the nose cone ispositioned within the die gap. The single barrel housing the augersystem may be positioned so as to create the die gap between the statorand rotor. In some embodiments, the die gap may be between about 1.35 toabout 1.8 mm. The positioning step places the single barrel with its twoaugers such that the fingers of the rotatable plate surround at least aportion of the downstream ends of the two augers. The fingers may alsosurround the downstream ends of the two augers in one embodiment or maybe in close proximity to the downstream ends from between about 2 toabout 6 mm in distance in one embodiment. The feeding step comprises afeed rate for raw materials of between about 200 to about 550 lbs/hr. Inone embodiment, the feeding step comprises a feed rate of between about400 to about 550 lbs/hr. In one embodiment, the feeding step comprises afeed rate of over 450 lbs/hr.

As described above, a wide range of raw materials is possible using theimproved rotary head extruder device described herein. The raw materialsmay comprise one or more of corn meal, whole grain corn meal, rice,whole grain flour, rice pea, brown rice, wheat flour, whole wheat flour,pea flour, black bean, pinto bean flour, potato flour, and other grainlegumes or tubers whether in flour, powder or other granular form.

Raw materials comprising a moisture between about 1.0% to about 18% maygenerally be used to form random extruded products in the rotary headextruder described herein. In one embodiment, the method may comprisethe step of pre-moistening or pre-hydrating the raw materials forintroduction into the rotary head extruder. In one embodiment, the rawmaterials comprise an initial moisture content of between about 11% toabout 12.5%. Raw materials may be pre-hydrated to from about 14.5% toabout 18% moisture by weight. In one embodiment, the raw materials arepre-hydrated to about 16.9% in-barrel moisture content by weight. In oneembodiment, the method may comprise the step of pre-mixing rawmaterials, which may include mixing one type of raw material with wateror with other raw materials with water for moistening prior tointroduction into the improved rotary head extruder. In this way,different materials can be moistened to the same approximate moisturelevel, for example.

During extrusion, and perhaps more specifically, the conveying step,both augers co-rotate and intermesh, whether independent of one anotheror not, in the same direction and/or speed. In one embodiment, a twinshot gear box may be used to rotate both augers simultaneously, or asingle gear box with one motor moves two shafts. In one embodiment, eachauger may comprise its own gear box to co-rotate independent of oneanother at the same speed. In one embodiment, the conveying step maycomprise an auger speed of about 100 to 400 rpm. Typically, the die gapremains constant during extrusion once the single barrel (and its thetwo augers) and rotor is positioned to set the gap, with only smalladjustments if necessary in the range of +/−0.5 mm. The temperature ofthe stator head may range from between about 260 to about 320F. In someembodiments, the rotor speed may be adjusted to from about 250 to about600 RPM.

The method further comprises the step of expanding the raw materialsinto a food product comprising a bulk density of between about 3.0 and11 lbs./cu ft, most preferably between 3.0 and 6.5 lb/cu ft. In oneembodiment, expanded and puffed food product comprises a bulk density ofbetween about 4.5 and about 5.0 lbs./cu ft. A cutting step may also beused to cut the expanded and puffed food product to a desirable size.

By way of example, FIG. 6 depicts a random extrusion processing lineinto which the rotary head extruder described herein may be introduced.Briefly, as shown in FIG. 6, in a first step of a random extrusion line,a mixer 60 adds moisture as it mixes the raw materials. The mixer may bevertical, as depicted in FIG. 6, or horizontal (not pictured). The rawmaterials are then transferred to a bucket elevator 42, which elevatesthe materials to the hopper 64 of the rotary head extruder. Next,extrusion forms hard dense extruded product utilizing rotating brassplates, as previously discussed above. The product is then conveyed 66to a fines tumbler 68, which removes small fines from the product. Theproduct then passes through a vibratory feeder 70 to provide even feedto a fryer 72, such as a rotary fryer, which decreases moisture and addsoil to the extruded product. Next, an additional vibratory feeder 74transfers product to a coating tumbler 76, wherein oil, flavor and saltare mixed. The products can then be turned in a flavor drum 57, whereinflavor is applied to the surface of the random collets.

It should be noted that while FIG. 6 describes a process for producingfried random corn collets, such illustration is not meant to limit thescope of this embodiment. In one embodiment, the rotary head extruderdescribed herein may be incorporated into a fried corn collet productionline for producing fried corn collets. In one embodiment, the rotaryhead extruder described herein may be incorporated into a baked corncollet production line for producing baked corn collets.

The invention will now be further elucidated with reference to thefollowing examples, which should be understood to be non-limitative. Itshould be appreciated by those of ordinary skill in the art that thetechniques disclosed in the examples that follow represent onesdiscovered by the inventors to function well in the practice of theinvention and thus, constitute exemplary modes. One of ordinary skill inthe art, when armed with this disclosure, should appreciate that manychanges can be made in the specific embodiments while still obtainingsimilar or like results without departing from the spirit and scope ofthe present invention.

EXAMPLE 1. WHOLE GRAIN BLEND

A mixture of whole grain cornmeal and yellow corn meal are blended tocreated a whole grain blend for extrusion and formation of whole grainrandom collets. The mixture comprises 55% whole grain cornmeal and 45%standard cornmeal. The mixture is introduced into a mixer and 4-7% wateris added. The mixture was mixed to moisten the whole grain blend untilit achieved a moisture content of about 15-18% . The particle sizedistribution of this particular cornmeal is between 100 and 700 micronswith up to 58% comprising particle size of about 425 microns. Anin-barrel moisture content of about 15.9% was determined. The rotorposition or gap was set to about 1.52 mm, and the stator headtemperature was recorded to be about 146C. The auger speed was initiallyset to about 228 rpm and the rotor comprised a rotor speed of about 500rpm. Product rate was measured to be about 467 lb/minute, with resultingexpanded, puffed product resulting with a bulk density of about 4.75lbs/cu ft.

EXAMPLE 2. RICE FLOUR BLEND 1

A mixture of rice flour, yellow corn meal and yellow pea flour wasblended to create a rice flour blend for extrusion and formation of riceflour random collets. The mixture comprised about 60% rice flour, 30%corn meal, and 10% yellow pea flour. All percentages are by weightunless otherwise disclosed. The mixture is introduced into a mixer and7% water is added. The mixture was mixed to moisten the whole grainblend until it achieved a moisture content of about 17.5%. The rotorposition or gap was set to about 1.60 mm, and the stator headtemperature was recorded to be about 132° C. The auger speed wasinitially set to about 275 rpm and the rotor comprised a rotor speed ofabout 530 rpm. Product rate was measured to be about 400 lb/minute, withresulting expanded, puffed product resulting with a bulk density ofabout 5.5 lbs/cu ft.

EXAMPLE 3. RICE FLOUR BLEND 2

A mixture of rice flour, yellow corn meal and yellow pea flour wasblended to create a rice flour blend for extrusion and formation of riceflour random collets. The mixture comprised about 55% rice flour, 30%whole-grain corn meal, and 15% yellow pea flour. All percentages are byweight unless otherwise disclosed. The mixture is introduced into amixer and 7% water is added. The mixture was mixed to moisten the wholegrain blend until it achieved a moisture content of about 17%. The rotorposition or gap was set to about 1.60 mm, and the stator headtemperature was recorded to be about 139° C. The auger speed wasinitially set to about 275 rpm and the rotor comprised a rotor speed ofabout 530 rpm. Product rate was measured to be about 340 lb/minute, withresulting expanded, puffed product resulting with a bulk density ofabout 5.2 lbs/cu ft.

The use of any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention. Unless otherwise defined, all technical and scientificterms and abbreviations used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which the inventionpertains.

The method illustratively disclosed herein suitably may be practiced inthe absence of any element that is not specifically disclosed herein. Insome embodiments, the methods described herein may suitably comprise orconsist only of the steps disclosed. Similarly, the formulations maycomprise or consist only of the components disclosed. Individualnumerical values and/or ranges are stated as approximations as thoughthe values were preceded by the word “about” or “approximately.” As usedherein, the terms “about” and “approximately” when referring to anumerical value shall have their plain and ordinary meanings to a personof ordinary skill in the art to which the disclosed subject matter ismost closely related. It should be understood that the exact valuefollowing the term “about” or “approximately” is also a suitable rangeor value without the approximate terms.

While this invention has been particularly shown and described withreference to preferred embodiments, it will be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention.The inventors expect skilled artisans to employ such variations asappropriate, and the inventors intend the invention to be practicedotherwise than as specifically described herein. Accordingly, allmodifications and equivalents of the subject matter recited in theclaims appended hereto are included within the scope of the claims aspermitted by applicable law. Moreover, any combination of theabove-described elements in all possible variations thereof isencompassed unless otherwise indicated herein or otherwise clearlycontradicted by context.

What is claimed is:
 1. A rotary head extruder comprising: a twin augersystem comprising two rotatable augers within a single barrel and atransition piece at a downstream end of the rotatable auger, saidtransition piece comprising an interior conical downstream portion; adie assembly comprising a stator and a rotor with a die gap therebetween, the die assembly downstream of the interior conical downstreamportion.
 2. The rotary head extruder of claim 1 wherein the transitionpiece comprises a figure eight opening and an interior conical flowpath.
 3. The rotary head extruder of claim 1 wherein the die gap isbetween about 1.35 and about 2.54 mm during operation of the extruder.4. The rotary head extruder of claim 1 wherein the stator comprises astator head section with interior grooves in communication with aconical shape, said conical shape having a slope extending out to meetthe interior grooves of the stator head section.
 5. The rotary headextruder of claim 4 wherein the slope begins at a location behind adownstream end of the two augers and extends out to the interiorgrooves.
 6. The rotary head extruder of claim 1 wherein the twin augersrotate simultaneously.
 7. The rotary head extruder of claim 1 whereinthe twin augers rotate at speeds of between about 100 to about 400 rpm.8. The rotary head extruder of claim 1 wherein the two augers arepositioned horizontally within the single barrel.
 9. A method of randomextrusion comprising the steps of: feeding raw materials into a singlebarrel comprising two augers within the single barrel; conveying the rawmaterials towards a die assembly through an intermeshing mechanism ofthe augers and through a transition piece having an interior conicalflow path, said interior conical flow path adjacent to a downstream endof the augers and said die assembly comprising a stator and a rotor witha die gap there between, wherein the stator is a stationary platesurrounding an output end of the transition piece and the rotor is arotatable plate downstream from the stator, the rotatable platecomprising a plurality of fingers surrounding a protruding nose cone ofthe rotor located within the die gap.
 10. The method of claim 9 whereinthe feeding step comprises a feed rate of between about 200 to about 550lbs/hr.
 11. The method of claim 9 wherein the raw materials comprise anin-barrel moisture content of between about 14.5% to about 18%.
 12. Themethod of claim 9 wherein the raw materials comprise one or more ofwhole grain corn meal, rice, whole grain flour, rice pea, brown rice,wheat flour, whole wheat flour, pea flour, black bean, pinto bean flour,potato flour, and other grain legumes or tubers whether in flour, powderor other granular form.
 13. The method of claim 12 wherein the rawmaterials further comprise corn meal.
 14. The method of claim 9 whereinthe conveying step comprises an auger speed of about 100 to about 400rpm.
 15. The method of claim 9 comprising the step of expanding the rawmaterials within the die assembly into a food product comprising a bulkdensity of between 3.0 and 6.0 lbs/cu ft.
 16. The method of claim 15wherein the food product comprises a final moisture content of less thanabout 3%.
 17. The method of claim 9 wherein the die gap is between about1.35 mm to about 2.54 mm.
 18. The method of claim 9 wherein thetemperature at the stator head is between about 260 to about 320F.
 19. Arandom extruded product comprising: a first granular food material andup to 55% of a second granular food material comprising a cereal orlegume flour, wherein said second granular food material is a foodmaterial other than the first granular food material; a bulk densityranging from about 3.0 to about 6.0 lbs/cu ft; a moisture content ofless than about 3%.
 20. The random extruded product of claim 19comprising a third granular material.
 21. The random extruded product ofclaim 19 wherein the first granular food material is a corn meal. 22.The random extruded product of claim 19 wherein the second granular foodmaterial is whole grain corn meal.
 23. The random extruded product ofclaim 20 wherein the third granular material is yellow pea flour in anamount of between about 10% to about 15%.
 24. The random extrudedproduct of claim 19 comprising about 30% yellow corn meal.
 25. Therandom extruded product of claim 19 wherein the second granular foodmaterial is rice flour.
 26. The random extruded product of claim 25comprising about 60% rice flour.